package cn.qixin.passport.filter;

import cn.qixin.passport.security.LoginPrincipal;
import cn.qixin.passport.web.JsonResult;
import cn.qixin.passport.web.ServiceCode;
import com.alibaba.fastjson.JSON;
import io.jsonwebtoken.*;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.filter.OncePerRequestFilter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

@Slf4j
@Component
public class JwtAuthorizationFilter extends OncePerRequestFilter {

    @Value("${qixin.jwt.secret-key}")
    private String secretKey;
    public static final int JWT_MIN_LENGTH = 113;
    @Override
    protected void doFilterInternal(HttpServletRequest request,
                                    HttpServletResponse response,
                                    FilterChain filterChain) throws
                            ServletException, IOException {
        log.debug("JwtAuthorizationFilter开始执行过滤……");
        log.debug("开始执行清空Security上下文...");
        SecurityContextHolder.clearContext();

        log.debug("正在获取客户端的jwt...");
        String jwt = request.getHeader("Authorization");
        log.debug("获取客户端携带的JWT：{}", jwt);
        log.debug("开始检查jwt是否有效");
        if (!StringUtils.hasText(jwt) || jwt.length() < JWT_MIN_LENGTH) {
            log.debug("获取到的JWT被视为无效，当前过滤器将放行……");
            filterChain.doFilter(request, response);
            return;
        }

        log.debug("获取到的JWT被视为有效，准备解析JWT……");
        response.setContentType("application/json; charset=utf-8");
        Claims claims = null;

        try {
            claims = Jwts.parser()
                    .setSigningKey(secretKey)
                    .parseClaimsJws(jwt)
                    .getBody();
        } catch (ExpiredJwtException e) {
            log.debug("解析JWT时出现ExpiredJwtException");
            String message = "登录信息已过期，请重新登录！";
            JsonResult<Void> jsonResult = JsonResult.fail(ServiceCode.ERR_JWT_EXPIRED, message);
            String jsonResultString = JSON.toJSONString(jsonResult);
            PrintWriter writer = response.getWriter();
            writer.println(jsonResultString);
            return;
        } catch (MalformedJwtException e) {
            log.debug("解析JWT时出现MalformedJwtException");
            String message = "非法访问！";
            JsonResult<Void> jsonResult = JsonResult.fail(ServiceCode.ERR_JWT_MALFORMED, message);
            String jsonResultString = JSON.toJSONString(jsonResult);
            PrintWriter writer = response.getWriter();
            writer.println(jsonResultString);
            return;
        } catch (SignatureException e) {
            log.debug("解析JWT时出现SignatureException");
            String message = "非法访问！";
            JsonResult<Void> jsonResult = JsonResult.fail(ServiceCode.ERR_JWT_SIGNATURE, message);
            String jsonResultString = JSON.toJSONString(jsonResult);
            PrintWriter writer = response.getWriter();
            writer.println(jsonResultString);
            return;
        } catch (Throwable e) {
            log.debug("解析JWT时出现Throwable，需要开发人员在JWT过滤器补充对异常的处理");
            e.printStackTrace();
            String message = "你有异常没有处理，请根据服务器端控制台的信息，补充对此类异常的处理！！！";
            PrintWriter writer = response.getWriter();
            writer.println(message);
            return;
        }
        log.debug("正在从jwt中获取当事人信息");
        Long id = claims.get("id", Long.class);
        String username = claims.get("username", String.class);
        String authoritiesJsonString = claims.get("authoritiesJsonString", String.class);

        log.debug("正在从jwt中获取权限信息");
        List<SimpleGrantedAuthority> authorities
                = JSON.parseArray(authoritiesJsonString, SimpleGrantedAuthority.class);

        log.debug("正在获取用户验证信息...");
        LoginPrincipal loginPrincipal = new LoginPrincipal(id, username);
        Authentication authentication
                = new UsernamePasswordAuthenticationToken(
                loginPrincipal, null, authorities);

        log.debug("向SecurityContext中存入认证信息：{}", authentication);
        SecurityContextHolder.getContext().setAuthentication(authentication);

        log.debug("JWT过滤器执行完毕，放行！");
        filterChain.doFilter(request, response);

    }
}
